Nelson Mandela is dead. The world is full of TV documentaries, newspaper and magazine articles, and blog posts about his life. Most of these are reverent tributes to Mandela’s remarkable contributions to freedom and equal rights for the oppressed, while a few loud voices attempt to paint him as a villain. I haven’t been following the media coverage too closely; there is no need. The figure of Nelson Mandela has loomed large in my consciousness for most of my life. I will not attempt to retell his story here – there are far better sources you can find easily enough. Rather, I want to share with you how Nelson Mandela’s life has influenced mine.

I may be the only person in the world to become aware of apartheid because of a model airplane. I was thirteen years old, and building model airplanes was my main hobby. (For the benefit of my younger readers, “hobbies” were things people used to do before there were smartphones.) I had just finished assembling a Dassault Mirage jet fighter, and the only thing left to do was paint the camouflage and fasten the decals. There were two patterns diagrammed in the instructions: a rather boring French Air Force paint scheme, and a much more exciting one unlike any I had seen. It showed the whole airplane painted like a cheetah, snarling head and all, and it was South African Air Force. It looked fantastic, and I went to find my father and show him what I was going to do.

“Paint the French one,” he said, to my amazement. Then he explained how South Africa was a populous nation of black people ruled by a small white minority through the brutal enforcement of an evil policy called apartheid. I had never heard that word before – like most Norwegian kids in the early 80’s, I was as ignorant about South Africa as I was about Africa in general. The truth was an unpleasant shock. I painted French colors on my Mirage.

Over the next few years, apartheid and South Africa grew increasingly in the public consciousness. By the time I was in high school, everyone knew that Nelson Mandela had been in prison for over twenty years for opposing apartheid in his own country. We sang “Free Nelson Mandela” between classes and listened to United Artists Against Apartheid singing “I ain’t gonna play Sun City” on our boomboxes after school. Social pressure became political pressure; the rest is history. International boycotts and trade embargoes, added to the disapproval of the global public, took their toll. The face of the entire anti-apartheid effort across the world belonged to a black man serving his third decade on Robben Island. When F.W. de Klerk became President of South Africa in 1989, he immediately began the process of ending his own government. Nelson Mandela was freed from prison in 1990. Blacks were allowed to vote for the first time in 1993, with the predictable result that Nelson Mandela became South Africa’s first black president.

I don’t suppose anyone knew what to expect next. It would have been very easy for Mandela to rub salt into the deep and painful wounds left by racist-motivated atrocities, to inflame the long-suffering hearts of black South Africans against their white countrymen with words of anger and hate. Instead, he did the right thing – which, as usual, was the hard thing – and chose a path of truth and reconciliation.

And that is Nelson Mandela’s legacy to me, whatever anyone else makes of him: maybe the only public figure of my lifetime to play the roles of prisoner and president, of revolutionary and reconciler, of torture victim and healer of a nation. Now, after having done so much, he has sloughed off this mortal coil.

A second grade classroom at my school incubated chicken eggs until they hatched. When their feathers had dried, the fluffy chicks looked too big to have been enclosed within the broken shells still lying in the incubator.

One of the eggs did not hatch. For some reason, the chick inside had gone lifeless and would never break out into the wide world. Mr. Watts, the teacher who had run the whole project, handed it to me. “Feel this,” he said. “It seems heavier than it was in the beginning.”

I gently shook the egg from side to side, feeling the dead weight shift within the shell. Truly, it felt heavier than the eggs I buy for omelets. Was it because this egg had been fertilized and transformed into a nearly-finished young bird? Is it possible for an egg to gain weight while the chick grows inside?

My first thought was that it could not have gained any mass, because it had not eaten anything from outside the shell. Everything inside an egg until it hatches was in there since the moment it was laid. The chick forms from a small part of the material, and absorbs most of the rest as it grows. Since it does not eat or absorb anything from outside the egg, it seemed unlikely that it would actually weigh more at the end of incubation than it had at the beginning.

Since I am not an expert in birds or their eggs, I decided to do some research. The best article I found was on the Poultry Club of Great Britain website, which you can read here if you like. According to the article, a healthy chicken egg loses about 13% of its mass during incubation. Otherwise, the chick does not have room to move around enough to break the shell with its egg tooth, and dies inside the egg as a result. Maybe that is what happened to the egg that inspired this article.

There was one other thing I was unsure of. A chicken breathes oxygen and wastes carbon dioxide, like all animals on Earth. Would it not have to breathe through the shell? If so, there might be gases coming into the egg from outside, which might add mass.

It turns out that there is an exchange of oxygen and carbon dioxide through the shell, but since carbon dioxide is heavier than oxygen, this would reduce, rather than increase, the egg’s mass; indeed, this is one of the reasons – humidity being the other – that the egg loses weight.

Why did the egg feel heavy? Probably because an unfertilized egg – like the ones I get at the grocery store for my omelets – is all liquid inside. The egg with the unhatched chick had much less liquid, a larger amount of air, and a solid mass shifting around, which gave an illusion of added weight. I am reminded of when my children were small. When they would fall asleep and I carried them to bed, they felt heavier than when I would give them a piggyback ride. Their limp and sleeping bodies felt heavier, even though their weight had not changed.

My sons are much too big and heavy for me to carry anymore. But getting old has nothing to do with the weight of chicken eggs, so I suppose this post is done.